Her imaging lab was in the farthest corner of the basement floor, which was underground on three sides with a main entrance to the rear, a rectangular hallway connecting the labs. Although the hallway was brightly lit, she could feel the weight of the earth and the darkness that waited beyond the waterproof concrete walls. It was early evening and much of the research section was empty, but a few doors were open. She didn’t glance in, lest someone call out to her in greeting.

She had a feeling she didn’t have much time.

She rounded the corner and saw two men outside the imaging lab. They were dressed like hospital interns in green scrubs, with cotton masks fitted over their mouths. The lab door was open.

“Hey!” she shouted.

The two men glanced at her, then each other. The taller one bolted to the left, where the hallway led back to the main entrance. He carried a white canvas bag in one gloved hand, and its bulk and sagging weight made her think it held machinery or books.

Alexis started after him but the second man stepped forward, blocking her path. She was so enraged by the invasion she didn’t consider that he might be armed.

“You’re not allowed access,” she shouted at the fleeing man, but he was already around the corner.

The remaining man spread his arms as if to tackle her if she tried to run past. Most of his body was covered, but his dark eyes and brown skin suggested someone of Indian or Middle Eastern descent. There was a large Indian and Pakistani population in the medical department, but she had a feeling this wasn’t an inside job.

“I’ve called the police,” Alexis said, hoping she sounded more commanding than she felt.

“We are the police,” the man said. She detected a Middle Eastern accent, but his voice was muffled enough that she couldn’t tell whether he was the same man who’d called. Had the caller wanted to tip her off, or send her into danger?